(a) Field of the Invention
For the coaxial epicyclic gear train with bidirectional input and one-way output, the external transmission structure of the epicyclic gear train integrates with the one-way transmission to implement the transmission operation with bidirectional input and one-way output for the epicyclic gear train; for the coaxial epicyclic gear train with bidirectional input and one-way output, if the input shaft is driven at the first rotary direction and at the second rotary direction, respectively, there are different transmission ratios occurring at the one-way output shaft, while there is same transmission ratio between the bidirectional input shaft and the one-way output shaft; thus the limitation of the coaxial gear train with bidirectional input and one-way output constituted by the planetary type transmission gear train is resolved, in which the internal transmission structure cannot make the transmission ratio between the input shaft driven at the first rotary direction and the output shaft and that between the input shaft driven at the second rotary direction and the output shaft without difference to implement one-way output.
(b) Description of the Prior Art
The conventional gear train with bidirectional input and constant rotary direction output is limited, which is constituted by the planetary type transmission gear train, because the internal transmission structure cannot make the transmission ratio between the input shaft driven at the first rotary direction and the output shaft and that between the input shaft driven at the second rotary direction and the output shaft without difference to implement one-way output.